The present invention relates to a system for transmitting power and converting torque mechanically so as to provide positive linkage between a power input shaft and a powered output shaft in ratios that can be infinitely varied, i.e. infinitely variable ratio or IV. The construction is an hybrid solution to the problem of enabling a gearbox to operate as a hydraulic torque converter, i.e. provide any input-to-output speed ratio between two limit values. The hydraulic analogy stems from the fact that the equivalent of a pump is provided and that the "fluid flow" of that pump drives the equivalent of a hydraulic motor. The "fluid" is replaced by mechanical links (balls) which can transmit pressure (push) but cannot exert suction (pull). Those mechanical links provide the positive mechanical connection between the shafts that eliminates the possibility of slippage and provides the additional possibility of positive locking.
Balls positioned between two surfaces enabled to slide relatively to each other have been used for transforming a sliding motion into a rotating motion (and vice versa) by means of cooperating grooves on both surfaces and arranged to constrain a ball. When properly guided and channelled, balls can provide the equivalent of a push rod that can follow and conform to a variety of curved shapes with a minimum of friction. The state-of-the-art of both technologies is old, extensively used in many applications and well known.
Efforts are continuously being made to develop variable speed ratio "gearboxes" that can provide progressively adjustable gear ratios for applications to transportation, i.e. cars, buses and/or trucks. The engine/vehicle coupling advantage offered by automatically adjustable gear ratios enables the engine to operate at its maximum efficiency regimes, be it from the fuel consumption or torque standpoints. This will result in appreciable fuel savings and improved vehicle performances.
In view of this background, the present invention provides those features, and combinations thereof, that are needed to substantially improve the efficiency and effectiveness of land vehicles, motorized or not. For the simplicity, the compactness and the light weight of its embodiments and constructions also make it very attractive for other transportation vehicles such as bicycles and motorcycles.